Optical systems for medical, theatrical, educational and other purposes involve the projection of high intensity light beams. One problem often arises in eliminating harmful effects of infra-red radiation. Use has been made of mirrors, known as cold-light mirrors, whose reflectance is restricted to limited wavelength bands. These produce the required intensity of light in the reflected beam.
Many different types of cold-light mirrors have been produced. Some utilize all polymer construction. Others form multiple dielectric layers on a glass substrate. One such device involves the use of a pigmented vitreous layer formed on a metal substrate in combination with multiple layers of quarter wavelength having alternating high and low indices. A decoupling layer may also be required between the pigmented layer and the multiple layers. Prior cold-light mirrors suffer from poor heat management capabilities, or difficulty in manufacture due to the inability to form different types of layers in a single processing machine.